In a wireless communication device such as a mobile phone, in order to connect a transmitting circuit and a receiving circuit to an antenna, or to perform communication by switching among frequency bands, a high-frequency semiconductor switch, which is called a single-pole n-throw (SPnT) switch, is connected between the antenna and the transmitting receiving circuits. Examples of a switching element in the high-frequency semiconductor switch include a metal-oxide-semiconductor field-effect transistor (MOSFET) provided on a silicon-on-insulator (SOI) substrate.
In recent years, it has become possible to use various communication frequencies in such devices as mobile phones or the like, and thus the number of high-frequency components, such as the transmitting circuit, the receiving circuit, and filters which are included in a wireless communication device tends to increase so communication can be conducted using the various communication frequencies. Since the size of the wireless communication device is limited, miniaturization of these high frequency components is desirable.